/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.wl4g.dopaas.uds.service.elasticjoblite.repository.impl;

import com.wl4g.dopaas.uds.service.elasticjoblite.exception.JobConsoleException;
import com.wl4g.dopaas.uds.service.elasticjoblite.repository.XmlRepository;
import com.wl4g.dopaas.uds.service.elasticjoblite.util.HomeFolderUtils;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import java.io.File;

/**
 * Abstract XML repository implementation.
 *
 * @param <E>
 *            type of data
 */
public abstract class AbstractXmlRepositoryImpl<E> implements XmlRepository<E> {

	private final File file;

	private final Class<E> clazz;

	private final JAXBContext jaxbContext;

	protected AbstractXmlRepositoryImpl(final String fileName, final Class<E> clazz) {
		file = new File(HomeFolderUtils.getFilePathInHomeFolder(fileName));
		this.clazz = clazz;
		HomeFolderUtils.createHomeFolderIfNotExisted();
		try {
			jaxbContext = JAXBContext.newInstance(clazz);
		} catch (final JAXBException ex) {
			throw new JobConsoleException(JobConsoleException.SERVER_ERROR, ex.getMessage());
		}
	}

	@SuppressWarnings("unchecked")
	@Override
	public synchronized E load() {
		if (!file.exists()) {
			try {
				return clazz.newInstance();
			} catch (final InstantiationException | IllegalAccessException ex) {
				throw new JobConsoleException(JobConsoleException.SERVER_ERROR, ex.getMessage());
			}
		}
		try {
			return (E) jaxbContext.createUnmarshaller().unmarshal(file);
		} catch (final JAXBException ex) {
			throw new JobConsoleException(JobConsoleException.SERVER_ERROR, ex.getMessage());
		}
	}

	@Override
	public synchronized void save(final E entity) {
		try {
			Marshaller marshaller = jaxbContext.createMarshaller();
			marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
			marshaller.marshal(entity, file);
		} catch (final JAXBException ex) {
			throw new JobConsoleException(JobConsoleException.SERVER_ERROR, ex.getMessage());
		}
	}
}
